典型氯碱污染场地环境风险评价

以广东某氯碱化工污染场地为研究区域,采集了场地22个土壤及地下水样品,分析了25项污染物在不同区域的分布特征及其来源。监测结果表明,煤炭堆场与锅炉房区土壤受重金属铅、镍污染。六六六、四氯化碳、三氯甲烷、六氯苯、苯是场地的特征污染物,主要分布在危险品仓库、漂洗车间与四氯化碳车间。根据监测结果开展了不同暴露途径致癌风险值及非致癌危害商的计算。结果表明,部分样品表层土壤中上述有机污染物的基于人体健康致癌风险指数均超过10-6,最高达到1.65×10-2,表明风险水平高;非致癌危害在各暴露途径下也超过可接受值1,最高达5.59×104,表明风险水平高。说明对于存在高风险的区域必须进行采取合适的措施进行修复,减缓场地再利用后对人群健康的影响。

Environmental risk assessment in a typical chlor-alkali contaminated site

A total of 25 pollutants were investigated for their spatial distributions and sources in a typical chlor-alkali contaminated site in Guangdong Province based on 22 soil and groundwater samples collected from the study region. Results showed that the coal yard and boiler room area were mainly polluted by heavy metals lead and nickel. BHC, carbon tetrachloride, chloroform, hexachlorobenzene, and benzene were the venue features pollutants, which distributed mainly in the regions of dangerous goods warehouse, rinse workshop and carbon tetrachloride workshop. The carcinogenic and non-carcinogen risk index were calculated in different exposure pathways for the pollutants of BHC, carbon tetrachloride, hexachlorobenzene and benzene. The results showed that the carcinogenic risk index of organic pollutants in surface soil is over 10^-6, with a maximum value of 1.65×10^-2; and the non-carcinogen risk index exceeds the acceptable risk value, with a maximum non-carcinogen index value of 5.59×10⁴. The analyses of human health risks indicated that an important portion of the population is at risk, and some appropriate measures should be adopted to remediate the contaminated site.